feat(frontend): add API client, layout, and routing

- Create Axios-based API client with sources, jobs, and dashboard endpoints
- Add responsive Layout component with navigation sidebar
- Set up React Router with Dashboard, Backups, and Settings routes
- Configure TanStack Query provider with default options
- Use lucide-react for navigation icons

frontend/node_modules/d3-time-format/locale/sv-SE.json

@@ -0,0 +1,10 @@
+{
+  "dateTime": "%A den %d %B %Y %X",
+  "date": "%Y-%m-%d",
+  "time": "%H:%M:%S",
+  "periods": ["fm", "em"],
+  "days": ["Söndag", "Måndag", "Tisdag", "Onsdag", "Torsdag", "Fredag", "Lördag"],
+  "shortDays": ["Sön", "Mån", "Tis", "Ons", "Tor", "Fre", "Lör"],
+  "months": ["Januari", "Februari", "Mars", "April", "Maj", "Juni", "Juli", "Augusti", "September", "Oktober", "November", "December"],
+  "shortMonths": ["Jan", "Feb", "Mar", "Apr", "Maj", "Jun", "Jul", "Aug", "Sep", "Okt", "Nov", "Dec"]
+}